I'd agree with the more critical takes. I've read something like 3/4 of his collected short non-fic at this point and it's very uneven, and the gems one does find among the rest tend to be of the semi-precious sort.
https://www.newyorker.com/magazine/2011/12/19/the-sanctuary https://www.newyorker.com/magazine/2011/03/07/the-view-from-... https://www.newyorker.com/magazine/2015/08/31/the-big-dig
The second one looks a lot like snarky "I'm the only cool person here" journalism, but IMO that sort of (typically bad) journalism exists in large part because Wallace could do it really well.
Oops, I misread your comment as "what", not whom. For whom, I dig George Saunders. Here's a piece he wrote about a visit to the mysterious "Buddha boy" a while back [3]. Saunders to me is pretty much Wallace's spiritual successor as far as style and tone goes.
[1] http://www.esquire.com/sports/a5151/the-string-theory-david-...
[2] https://harpers.org/wp-content/uploads/2008/09/HarpersMagazi...
[0] http://www.nytimes.com/2006/08/20/sports/playmagazine/20fede...
I like Orwell and Twain, but I think everyone does. I'm a bigger fan of E.M. Forster's non-fic than he perhaps deserves, because his prose feels really familiar and comfortable to me—and maybe he's better than the credit I'm giving him, but I recognize him as a possible blind spot for me and so downplay my recommendation.
Asimov's short non-fic is of a very different sort (to put it mildly) from, say, Wallace, and isn't at all impressive by some measures, but I like it anyway. The pieces are well constructed and competently written, like his fiction, but neatly avoid requiring much in the way of characters or dialog, which is a very good thing for Asimov. They're mostly descriptive rather than "thinky" or philosophical. It's like reading really pleasantly-written and didactically-minded Wikipedia articles with short, silly, mostly-unrelated anecdotes prefacing each one.
I've attempted Huxley but didn't make much progress. Then again I've also twice failed to finish Brave New World so the problem may be mine, not his.
I liked "Frank Sinatra Has a Cold".
Non-fic that makes it into Lapham's Quarterly is usually great, with the exception of Lapham's own introductions to each volume, which I usually set out intending to read and ultimately don't.
Wallace is the only recent author whose short non-fic I've read in significant quantity. His writing is certainly engaging, which is why I made it through so much. The prose is top-notch, in that one's eyes pass effortlessly down the page, interrupted only by Wallace's footnote fetish. He's mostly really fun. However, some of his best pieces come off like drafts of sections of longer, better works, which is to say the thinking's a little rough and they seem incomplete. I'm far from an advocate of minimal, straight-to-the-point writing, but most of Wallace's short non-fic works are longer than any insight they contain justifies (notable exception: the piece on Kafka) while also managing to leave a bunch of dark corners one wishes Wallace had explored—they're good at making you want to read something better on the same topic. He's often kind of mean for little reason other than pandering to the reader, as best I can tell, which is both compelling and off-putting in a car wreck sort of way. To be fair, he's also sometimes mean for a good reason. Still, when my kids are old enough for this kind of stuff I'll recommend a few pieces to them, though some for only narrow purposes ("gee dad, what was being in the Midwest on 9/11 like?", "here, read DFW on the topic, it's a weak piece but captures some of the details of the experience really well") or only reluctantly ("Host"—the bizarre style rarely improves the article, which is otherwise one of his better ones).